declare   @A nvarchar(200) ='大小'

declare @sql nvarchar(2000)
set @sql ='select *,(CONVERT(varchar(50),(size/128))+''MB'')' + @A +' from sysfiles'
exec (@sql)

------解决方案--------------------
SQL code
DECLARE @A INT
SET @A=888
declare @sql varchar(1000)
set @sql='SELECT NAME AS ['+ltrim(@A)+'] FROM TABLE'
exec(@sql)

------解决方案--------------------
写动态SQL 是可以的 
SQL code

DECLARE @A INT
SET @A=888
declare @s varchar(100)
set @s = 'select NAME AS '+convert(varchar(8),@a) + 'FROM TABLE'
exec (@s)

------解决方案--------------------
SQL code
DECLARE @A INT,@s varchar(100)
SET @A=888


set @s='SELECT NAME AS ['+ltrim(@A)+'] FROM Table'

exec(@s)

------解决方案--------------------
动态吧